1. Field of the Invention
The present invention relates to a control apparatus for a hydraulically operated vehicular transmission having a plurality of speed stages to be established by a selecting operation of a plurality of hydraulic engaging elements. In this specification, the term "vehicular transmission" means a transmission for a vehicle such as a motor vehicle.
2. Description of the Related Art
As this kind of apparatus, there has hitherto been known one in which a hydraulic pressure of that hydraulic engaging element on a disengaging side which is disengaged at the time of speed changing and a hydraulic pressure of that hydraulic engaging element on an engaging side which is engaged at the time of speed changing are electronically controlled by using solenoid proportional valves.
There are two kinds of speed changing, one of them being an ordinary speed changing to be performed according to a speed change map in a range (or position) of an automatic speed change, the other of them being a manual speed changing to be performed by switching of ranges between an automatic speed change range and a low-speed holding range, or by lever operation in a transmission in which speed change of one stage at a time can be made by lever operation.
At the time of manual speed changing, it is desired to enable to perform speed changing at a shorter time than at the time of the ordinary speed changing. For that purpose, it is considered to correct, by boosting, the hydraulic pressure of the hydraulic engaging element on the engaging side at the time of manual speed changing. However, if the hydraulic pressure is simply boosted, speed change shocks will become large.
In view of the above-described point, the present invention has an object of providing a control apparatus in which manual speed changing can be performed at a shorter time without giving rise to large shocks.